title: Overnight Sleep Enhances Hippocampus-Dependent Aspects of Spatial Memory.
abstract: OBJECTIVE
  Several studies have now demonstrated that spatial information is processed during sleep, and that posttraining sleep is beneficial for human navigation. However, it remains unclear whether the effects of sleep are primarily due to consolidation of cognitive maps, or alternatively, whether sleep might also affect nonhippocampal aspects of navigation (e.g., speed of motion) involved in moving through a virtual environment.
  
  
  METHODS
  Participants were trained on a virtual maze navigation task (VMT) and then given a memory test following either a day of wakefulness or a night of sleep. Subjects reported to the laboratory for training at either 10:00am or 10:00pm, depending on randomly assigned condition, and were tested 11 h later. Overnight subjects slept in the laboratory with polysomnography.
  
  
  METHODS
  A hospital-based academic sleep laboratory.
  
  
  METHODS
  Thirty healthy college student volunteers.
  
  
  METHODS
  N/A.
  
  
  RESULTS
  Point-by-point position data were collected from the VMT. Analysis of the movement data revealed a sleep-dependent improvement in maze completion time (P < 0.001) due to improved spatial understanding of the maze layout, which led to a shortening of path from start to finish (P = 0.01) rather than faster exploration speed through the maze (P = 0.7).
  
  
  CONCLUSIONS
  We found that overnight sleep benefitted performance, not because subjects moved faster through the maze, but because they were more accurate in navigating to the goal. These findings suggest that sleep enhances participants' knowledge of the spatial layout of the maze, contributing to the consolidation of hippocampus-dependent spatial information.
  
  
  BACKGROUND
  Nguyen ND; Tucker MA; Stickgold R; Wamsley EJ. Overnight sleep enhances hippocampus-dependent aspects of spatial memory.SLEEP2013;36(7):1051-1057.
authors.affiliation: Department of Psychiatry, Beth Israel Deaconess Medical Center, Boston, MA.
authors.forename: Nam D
authors.initials: ND
authors.lastname: Nguyen
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Tucker
authors.forename: Robert
authors.initials: R
authors.lastname: Stickgold
authors.forename: Erin J
authors.initials: EJ
authors.lastname: Wamsley
keywords: EEG; consolidation; learning; maze; procedural; speed